Along with the rapid market expansion of notebook personal computers, cell phones, electric cars and the like, high-energy density secondary batteries are in demand. Means of obtaining high-energy density secondary batteries include a method of using a large-capacity negative electrode material, and a method of using a nonaqueous electrolyte liquid excellent in stability.
Patent Literature 1 discloses the utilization of an oxide of silicon or a silicate salt for a negative electrode active substance of a secondary battery. Patent Literature 2 discloses a negative electrode for a secondary battery having an active substance layer containing a carbon material particle capable of occluding and releasing lithium ions, a metal particle capable of being alloyed with lithium, and an oxide particle capable of occluding and releasing lithium ions. Patent Literature 3 discloses a negative electrode material for a secondary battery, which is obtained by coating carbon on the surface of a particle having a structure in which microcrystals of silicon are dispersed in a silicon compound.
Patent Literature 4 discloses an electrolyte liquid containing a cyclic oxocarbon anion having the following structure.
(In the formula, R1 represents one group selected from the group consisting of hydrocarbon groups having 1 to 12 carbon atoms, halogen-substituted hydrocarbon groups, alkoxy groups, thioether groups, amino groups, amide groups and acyl group; and n is an integer of 1 to 6).